A series of explosions hit Aleppo University in Syria on Tuesday, killing an estimated 52 people and injuring dozens more. Once Syria’s commerical epicenter, the city of Aleppo has essentially been the site of almost constant violence since July, with insurgents and government forces locked in a stalemate over control of the city. The university, which is in a government-controlled part of the city, had been conducting classes as fighting went on. Antigovernment activists said university buildings had been hit by missiles fired by Syrian military forces. But SANA, Syria’s state-run news agency, indicated that the missiles had been fired by the insurgents.